Astronomy C

[bernard]

Astronomy Wiki
Astronomy Test Exchange 2018
Past Threads: 2009 (Variable Stars), 2010 (Galaxies), 2011 (AGNs), 2012 (Stellar Evolution & Type Ia Supernovae), 2013 (Stellar Evolution & Type II Supernovae), 2014 (Variable Stars & Stellar Evolution), 2015 (Star & Planet Formation), 2016 (Star Formation & Exoplanets), 2017 (Type IA Supernova Events)
Past Question Marathons: 2014, 2015, 2016, 2017

[Unome]

Rule 2 has been revised to better indicate allowed resources - the changes are quite a bit clearer.

They've added gamma ray binaries, but everything else looks very similar to 2013 (besides the DSOs of course).

[Ashernoel]

For the DSO HR 5171 A, do you think the rules are referring to the Eclipsing Binary as "HR 5171 A" or the LBV in the binary as "HR 5171 A" according to a random catalog?

""The primary A is an eclipsing binary (components Aa and Ab, or A and C in the Catalog of Components of Double and Multiple Stars) "" Wikipedia

[CaldwellBrownies]

For the DSO HR 5171 A, do you think the rules are referring to the Eclipsing Binary as "HR 5171 A" or the LBV in the binary as "HR 5171 A" according to a random catalog?

""The primary A is an eclipsing binary (components Aa and Ab, or A and C in the Catalog of Components of Double and Multiple Stars) "" Wikipedia

The rules probably meant the actual binary system with Aa and Ab, since one of the focuses this year is on "orbital motions of binary systems." But I wouldn't be surprised if there was a question about the blue supergiant on tests.

I have a question: what does the "motions" portion of "using information which may include... light curves, motions" entail? And how would I study to prepare for that on tests?

[Unome]

For the DSO HR 5171 A, do you think the rules are referring to the Eclipsing Binary as "HR 5171 A" or the LBV in the binary as "HR 5171 A" according to a random catalog?

""The primary A is an eclipsing binary (components Aa and Ab, or A and C in the Catalog of Components of Double and Multiple Stars) "" Wikipedia

I would focus on the LBV since this year focuses on high-mass stellar evolution, but would still study both (though I'm sure you already will).

I have a question: what does the "motions" portion of "using information which may include... light curves, motions" entail? And how would I study to prepare for that on tests?

This is probably just radial velocity graphs except left more open-ended, since I don't think radial velocity graphs are specifically mentioned.

[Ashernoel]

For the DSO HR 5171 A, do you think the rules are referring to the Eclipsing Binary as "HR 5171 A" or the LBV in the binary as "HR 5171 A" according to a random catalog?

""The primary A is an eclipsing binary (components Aa and Ab, or A and C in the Catalog of Components of Double and Multiple Stars) "" Wikipedia

I would focus on the LBV since this year focuses on high-mass stellar evolution, but would still study both (though I'm sure you already will).

Ya I'm just worried about accepted answers on test because it refers to two different things.
Answering HR 5171 A and referring to the LBV instead of using HR 5171 Aa could end up in not receiving credit for the answer. Likewise, answering HR 5171 Aa when referring to the LBV instead of a supervisor's desired HR 5171 A would also result in no credit.

I think a FAQ or clarification of whether the A in the rules refers to the LBV or the eclipsing binary would clear everything up... :3

If there isn't one I'll assume it refers to the EB because it only refers to the LBV in that one catalogue....

[Magikarpmaster629]

For the DSO HR 5171 A, do you think the rules are referring to the Eclipsing Binary as "HR 5171 A" or the LBV in the binary as "HR 5171 A" according to a random catalog?

""The primary A is an eclipsing binary (components Aa and Ab, or A and C in the Catalog of Components of Double and Multiple Stars) "" Wikipedia

I would focus on the LBV since this year focuses on high-mass stellar evolution, but would still study both (though I'm sure you already will).

Ya I'm just worried about accepted answers on test because it refers to two different things.
Answering HR 5171 A and referring to the LBV instead of using HR 5171 Aa could end up in not receiving credit for the answer. Likewise, answering HR 5171 Aa when referring to the LBV instead of a supervisor's desired HR 5171 A would also result in no credit.

I think a FAQ or clarification of whether the A in the rules refers to the LBV or the eclipsing binary would clear everything up... :3

If there isn't one I'll assume it refers to the EB because it only refers to the LBV in that one catalogue....

The answer to "which DSO is it really?" is always "all of them." There's no such thing as too much info, this is why you're allowed a laptop.

Realistically, I think the problem will be test writers seeing the reason behind why this DSO is on the list. Chances are it'll just be treated like any other and you'll get the standard identify it from different wavelength images, how was it discovered/how did it affect the study of objects like it and astronomy more generally, what are some special/abnormal properties, etc.

[raxu]

Emission Nebula and H II region seems similar: the Sharpless Catalog targets H II regions, but seem to have included other emission nebulae as well...

My understanding: Emission nebula is any nebula that emits light through ionized gas, and H II region is one with ionized hydrogen. Furthermore, in H II the Hydrogen is ionized by the radiation of young stars that just formed, while other emission nebulae are ionized by stars that just died (hence containing other elements). Is that accurate?

[Unome]

Question: Why do gamma ray images often have so much background noise? I would think that, being mostly the result of energetic rare events, they wouldn't be that common in the background.

Emission Nebula and H II region seems similar: the Sharpless Catalog targets H II regions, but seem to have included other emission nebulae as well...

My understanding: Emission nebula is any nebula that emits light through ionized gas, and H II region is one with ionized hydrogen. Furthermore, in H II the Hydrogen is ionized by the radiation of young stars that just formed, while other emission nebulae are ionized by stars that just died (hence containing other elements). Is that accurate?

This seems accurate to me, though I don't know too much about this.

[Unome]

For anyone who's curious, the two distance measurements for NGC 6357 appear to originate here (~1.7 kpc) and here (~2.6 kpc). I've yet to figure out which of these would be more likely to be accepted by event supervisors (or whether to vary my answer depending on the conditions).